A police chief in Northeast China is being investigated over online claims he gave promotions to twin sisters he was sexually involved with.

Qi Fang, director of public security for the Xinjiang Uygur autonomous region's Usu city, is being probed by the Party anti-graft agency.

But information related to the allegations and investigation is unclear, with one police official saying Qi is still on the job and another saying the reports of sexual misconduct are patently false.